Steel ball bearing roller assembly for sliding patio door.

Its wheel is center grooved with diameter of 1-1/4 inch
Its housing is constructed out of Steel and is adjustable
This design is used by door manufacturers including Ador Hilite

Housing Tab Style: Unique Housing
Housing Width: 3/4-inch
Roller Diameter: 1-1/4-inch
Roller Edge Type: Concave
Roller Material: Steel
Roller Width: 5/16-inch

Contents
1 roller assembly

Priced and sold each.

Helpful Article: Replacing Rollers in an Aluminum Sliding Glass Door.